Sewing machine



ay 10, 1938. c. s. THOMPSON ET AL 2,116,987

SEWING MACHINE I Filed-March 4, 1956 s Sheets- Sheet 1 mvmmzes: Charms S. Thompson Fran]: H. ifucara Ix.

filimrf/ ,5 Riviera RNEYS.

y 1938- c. s. THOMPSON ET AL 2,116,987

SEWING MACHINE Filed March 4, 1936 5 Sheets-Sheet 2 mvzwwozs: Charles S. T/wm 1 fl ifuwra A; flliwrt S. K

Fran]:

ATTORNEYS.

ay 10, 1938. c. s. THOMP SON ET AL 2,116,937

SEWING MACHINE Filed March 4, 1956 3 Sheets-SheetE mvzflroxs: W1 TNESSES: Charm; 5. Thompson Frank H. Human KL ORNEYS.

Patented May 10, 1938 UNITED STATES PATENT OFFICE SEWING MACHINE Application March 4, 1936, Serial No. 67,028

2 Claims.

This invention relates to sewing machines; and it has reference more particularly to sewing machines designed for attaching binding tape or other strip material about the edge of a body fabric, as, for example, in finishing underwear and the like.

In the operation of such machines, difficulty has been experienced heretofore in effecting uniform longitudinal folding of the binding strip and even application of the same about the edge of the body fabric, especially when the binding strip is of knitted material which is elastic and which has a tendency to curl along its edges.

Our invention is directed toward overcoming the drawback of which mention has just been made. This objective we realize in part, as hereinafter more fully disclosed, through provision of a folding device capable of effectively flattening out the edge curls of the binding strip, as well as of maintaining said strip under definite control while progressively folding it longitudinally, so that it is evenly folded with its fold margins perfectly fiat and so placed about the edge of the body fabric concurrently as the latter is advanced to the stitch forming instrumentalities of the sewing machine. Accordingly in the fin-- ished product, the seam stitches will pass through but three thicknesses of material instead of five as ordinarily when the edges of the binding strip are turned under or hemmed. Thus, through our invention it is possible to produce a smoother, neater and less bulky edging than heretofore, and at the same time effect a great saving in material by reason of the narrower strip material employed.

A further object of our invention is to provide for cooperation with a folder having the foregoing attributes, main and auxiliary tensioning devices which can be independently adjusted, and which, moreover, can be relied upon to maintain the binding strip uniformly taut and under a predeterminable constant degree of tension so that upon relaxing of the strip after being sewed to the body fabric, a smooth and undistorted edge finish is assured.

Other objects and attendant advantages will appear from the following detailed description of the drawings, wherein Fig. I shows, in front elevation, a sewing machine for applying strip binding about the edge of a body fabric conveniently embodying our invention.

Fig. II is a plan View of the machine with a portion of its overhanging arm broken away.

Fig. III is a perspective view on an enlarged scale of the folder with portions broken out and in section to better show the details of its construction.

Fig. IV is a plan View of the folder with the opposite end portions shown in longitudinal section.

Fig. V is a perspective view on a still larger scale of the delivery end of the folder showing how the folded binding strip is delivered and p0- sitioned, with its fold margins perfectly flat, about the edge of the body fabric to which it is to be 10 secured.

Fig. V1 is a view looking as indicated by the arrows VI--VI in Fig. V.

Fig. VTI is a fragmentary detail sectional view of the folder taken as indicated by the arrows 15 VII-VII in Fig. IH.

Fig. VIII is a fragmentary view partly in elevation and partly in section taken as indicated by the arrows VIIIVIII in Fig. I and showing the details of the main tensioning device by which the binding strip is tensioned before passing through the folder; and

Fig. IX is a perspective view of a guide associated with the tensioning means for the binding strip.

The sewing machine chosen for convenience of illustration herein has a hollow base I with a standard 2 rising from one end thereof and supporting an integrally-formed horizontal overhanging arm 3. Confined to axial movement in 30 a head l at the outer end of the arm 3 is a vertical needle bar 5, which, in this instance, carries two spaced needles 6 and 1 at its lower end. The needle bar 5 is reciprocated endwise by suitable mechanism concealed in the hollows of the ma- 5 chine frame, and is actuated through interposed connections (not shown), from a horizontal main shaft8 which is journaled within the base I and provided at its protruding right hand end with a combined hand and belt wheel 9. Also confined 40 to axial movement in the head 4 is a vertical presser bar [0, which, at its lower end, carries a presser foot ll, said presser bar being yieldingly urged downward by a leaf spring l2 mounted on the top of the overhanging arm 3 of the ma- 45 chine. Cooperating with the needles 6 and 1 above the top or work supporting surface l3 of the base I is a cover thread manipulating hook I5 which is actuated by suitable mechanism from within the head 4 and the overhanging arm 3, 50 the carrier arm 16 for said looper oscillating about the presser bar ll! as an axis. Cooperating with the needles 6 and 1 below the work supporting surface 13 of the base i is a looper I! which is fixed in a carrier arm I8 fulcrumed at IS on a rocker 25. By suitable connections (not illus trated) the rocker 25 is actuated from the main shaft 8 to impart the needle avoiding movements to the looper 5?. Through a horizontal link 2! and an oscillating arm 22 actuated from the main shaft 8 by connections also concealed within the base i, the looper H is rocked about the center it to engage the needle threads in a well known manner. In Fig. I, the needle threads are indicated at N, N, the cover thread at C, the looper thread at L, said threads all passing through suitable tensions and directional guides as shown, on their Way to the needles 5 and l, the hook l5 and the looper ll respectively. During the operation of the machine, the body fabric B is progressively advanced crosswise of the work supporting surface 15 by a feed dog indicated in dotted lines at 25 in Fig. I. Like the looper ll, the feed dog 55 is actuated by concealed mechanism coordinated with the main shaft it within the base i.

In adapting a sewing machine of the type briefly described up to this point for applying strip binding S about one edge of the body fabric 13 in the manner shown in Figs. II and V, we have devised the cooperative binding strip folder, and the main and supplemental strip tensioning devices which are about to be described.

The device for folding the strip material S is comprehensively designated 25, and has the form of a horizontally-elongated member to the back of which is secured, by means of screws 25, a vertically-slotted plate 21 for engaging the upstanding tongue 28 of a bracket 29 bolted to a supporting arm 35. As shown, the plate 2'! is provided with a set screw ill for securing the folder 25 in vertically adjusted positions on the tongue 28 of the bracket 29, while the supporting arm 35 is fulcrumed at 32 to the base i of the machine with capacity to be swung to the position indicated in dot and dash lines in Fig. II. By virtue of this arrangement, the folder 25 can be moved toward and away from the stitch forming instrumentalities of the machine when de sired or required. As shown in Fig. III, the folder 25 is fashioned from sheet metal and merges from a vertically-flat tubular cross section near its right hand or receiving end, see Fig. III, to a horizontally flat U-shaped tubular cross section at its left hand or delivery end, which latter has a bevel 53 at an angle of approximately forty-five degrees. The transverse dimension of the passage through the folder is uniform throughout and just slightly greater than the thickness of the binding strip. At the receiving end of the folder beyond the point 35, the upright back wall of said folder is extended as at 35, and the front wall is notched inward from the top and bottom as at 35 for reduction of its cross section, with incidental formation of a spring tongue 5? whereof the end is rounded outwardly as at 33. The top and bottom edges of the tongue 31, it will be noted, are divergent in the direction of travel of the binding strip S and rounded inwardly as at 39 toward the back wall 35 of the folder as they approach the notches 35. For a purpose later on explained, the tongue 3'5 and the front wall of the folder 25 are longitudinally slotted as at 40 and 55 respectively. At its left hand or delivery end, the folder 25 has a lateral inwardly directed outlet extension 62 which is of horizontal flat U shaped cross section and which serves as a guide for the edge of the body fabric 13, said extension having opposing flanges 43 at the top and bottom to guide the edges of the binding strip S after the latter is folded and providing a passage whereof the transverse dimension is substantially equal to the combined thicknesses of the body fabric and the two margins of said binding strip. The folder 25 is furthermore provided at the top and bottom near its delivery end with notches 45, see Figs. I, III, V, and VII which extend parallel with a bevel at 33, the portions 46 beyond the notches being thickened and rounded along one edge with formation of lips at M. As a result of this construction there is formed, also for a purpose later on explained, a constricted U- shaped mouth at the bevel of the folder of which the cross dimension is just equal to the thickness of the strip 8.

Located immediately to the right of the folder 25 is a binding strip tensioning device which is generally designated by the numeral 58, and

which comprises a vertically-arranged back plate 55, said plate being secured near its bottom edge to the front of the machine frame by a pair of screws 52, see Figs. I and VIII. Opposing the upper part of the back plate 5! is a clamp plate 53 which has a central stud 54 loosely engaged in the bifurcated upper end of the vertical supporting arm 55. At its lower end, the supporting arm 55 has a loose universal pivotal connection with a headed screw 56, and at its midpoint said arm has a boss 5'! which is axially apertured to clear a stem 58 projecting horizontally forward from the back plate 5|. Interposed between a shoulder on the boss 51 of the clamp plate 53 and a finger knob 59 in threaded engagement with the end of the stem 58 is a helical compression spring '56 which yieldingly urges said clamp plate toward the back plate 5! to impose frictional restraint upon the binding strip S. Associated with the finger knob 58 is a jam nut 51 for fixing said knob against accidental rotation after the desired adjustment of the spring fill is secured. A screw stud 62 projecting from the clamp plate 53 and loosely engaging an aperture of the supporting arm 55 serves to prevent rotation of said clamp plate about the axis of the stud 54. In order that the binding strip S may be relieved of tension when desired or required, there is provided a curved finger 55 which is fulcrumed about another screw 65 on the back plate 5! into which screw the fulcrum screw 56 for the clamp supporting arm 55 is axially threaded as shown in Fig. VIII. At its end the curved finger 65 has a cam surface G'l'adapted to cooperate with a rounded projection 63 at the back of the clamp plate supporting arm 55. Thus, as the finger 65 is swung anti-clockwise in Fig. I, the cam end 51 of the finger 55 is brought into engagement with the rounded projection 68 on the arm 55 with the result that the clamp plate 53 is moved away from the back plate 5| of the tensioning device against the action of the spring 60. Normally, the finger 55 is held in the retracted position shown in Fig. I by a spring 59 with the tail projection l8 thereof engaging a fixed stop H on the back plate 5|. On the other hand, when the finger 55 is actuated, its movement is limited by another fixed stop 12 on said back plate 5!. The tension release finger 65 may be operated by any suitable means, for example, through a wire connecting link 13 from a foot treadle or knee lever, not illustrated. Associated with the strip tensioning device 50 is an angular guide piece '15 (Figs. I, II, and IX) which is secured, with capacity for vertical adjustment, to the back plate 5! by a screw 16 pass- Ill all times.

ing through an elongate slot 11 therein. As strictedJU-shaped mouth at the bevel of the shown in Fig. IX, the guide piece 15 has a vertical slit 18 for the binding strip S, said slit, it will be particularly noted, being open at the top.

Also associated with the strip tension device 50 is the supplemental binding strip guide and tensioning device 80 which is supported by a lateral bracket arm extension 8| of the back plate As shown, the device 80 is in the form of an upright fork with spaced cylindric tines 82 and 83 betweenwhich the binding strip S passes. The tine 83 is fixed in a collar 84 rotatably adjustable about the tine 82, which, in turn, is anchored at the bottom in a lug 85 at the end of the bracket arm 8!. A finger screw 86 is provided for securing the collar 84 in adjusted positions.

The operation of the machine is as follows:

As hereinbefore stated, the body fabric B is progressively advanced crosswise of the work supporting surface l3 of the machine base I by the action of the feed dog 23. At the same time, the binding strip S is delivered by the folder 25 and placed, with its fold margins perfectly flat, about the edge of the body fabric B as said edge passes through the end guide portion 42 of said folder, and sewed fast to the body fabric through coaction of the needles 6, l, the cover thread hooks l5 and the looper ll. The seam thus produced is similar to that shown in another U. S. Patent No. 1,473,636 also granted to J. R. Moifatt on November 13, 1923, with a double row of stitches passing through both edges of the binding strip S and the body fabric B, and connected above and below by concatenation of the cover and looper threads between them, except in that the stitches formed by one of the needles penetrate but three thicknesses of material-the body fabric and the strip margins. Under the pull of the body fabric B, the binding strip S is drawn from a suitable source of continuous supply (not shown), passing horizontally upright first through the supplemental tensioning device 80, then through the main tensioning device 50, and finally through the folder 25. By rotative adjustment of the supplemental device 80, the binding strip S is diverted more or less from a straight course as shown in Fig. II and an initial drag consequently induced in it. In passing from the preliminary tensioning device 80 the binding strip S is directed, by the guide 15, between the plates 5| and 53 of the main tensioning device 50, which, by means of the finger knobs 59 and 60, can be adjusted to impose additional tension on said strip by frictionally restraining its progress. In leaving the main tensioning device 50, the binding strip passes into the receiving end of the folder 25, where, under the influence of the inwardly curved edges 39 of the tongue 31 any edge curls or irregularities therein are effectively removed. In reeving through the transversely narrow passage of the folder 25, the binding strip S is progressively folded longitudinally, with its margins constrained and held flat, by reason of the gradual mergence of said folder from vertically flat tubular cross section at the receiving end, to horizontally fiat U-shaped cross section at its delivery end, where the direction of travel of the strip is changed and the strip inverted or reversed as its folds pass about the bevel at 33 in the manner clearly shown in Figs. I and V. Due to the uniformity and narrowness of the transverse dimension of the passage in the folder, the traversing strip except for being longitudinally folded, is otherwise maintained perfectly fiat at As the strip passes through the refolder, it is obviously so confined and controlled that recurling of its edges cannot possibly reoccur. The flat condition of the strip margins is moreover maintained as the strip continues in its advance by the added tension imposed thereupon as it turns about the bevel edges and enters the lateral continuation 42 of the folder where it meets with the body fabric B. Here again, due to theconfining action of the guide extension 42 of the. folder, the strip margins are maintained perfectly fiat against the opposite edges of the body fabric, and so present-ed to the stitchforming instrumentalities of the sewing machine for seaming, positive registry of strip with the body fabric being assured by the action of the lips 43 of said extension. The purpose of the devices 50 and B0 is to impose considerable degree of tension on the binding strip, particularly if the latter is of knitted material and applied crosswise of the wales of a knitted body material. Thus, after the work passes beyond the stitch forming instrumentalities of the machine, a compensative relaxing action takes place between the body fabric and the strip, with the formation as a result, of a neat, non-bulky perfectly finished edging.

The guide functions to prevent sagging of the binding strip S in the tensioning device 50, and through proper adjustment, said guide will determine travel of the strip along a direct straight line to the folder 25.

Since the main tensioning device 50, the associated guide '15 and the supplemental tensioning device 80 are'all accessible for threading from the top, it is evident that the starting of the strip S through them initially is greatly facilitated. The longitudinal slotting of the folder at 40 and ll permits the use of a pointed implement in starting the strip S through said folder; while the notches 45 at the delivery end of the latter render the edges of the strip accessible for the purpose of flattening them out in the event that they become creased before reaching that point.

Having thus described our invention, we claim:

1. A folder for longitudinally folding a binding strip of knitted material or the like and continuously guiding it to the stitch-forming instrumentalities of a sewing machine with its fold margins lapping opposite sides of a concurrently fed body fabric, said folder having means beyond its receiving end for removing the natural curl at the edges of the strip so that the latter enters perfectly fiat, and being tubular and mergent from fiat cross section at its receiving end to U-shaped cross section at its delivery end with provision of an uninterrupted passage therethrough whereof the transverse dimension is substantially uniform and slightly greater than the thickness of the strip, whereby the strip edges are maintained fiat during traverse of the strip in the folder, and said folder having inwardlydirected opposing lips forming a constricted slit mouth at its U-shaped delivery end which constrains the strip folds throughout their widths and precludes reforming of the edge curls as the strip emerges and is applied about the edge of the body fabric.

2. A folder for longitudinally folding a binding strip of knitted material or the like and continuously guiding it to the stitch-forming instrumentalities of a sewing machine with its fold margins lapping opposite sides of a concurrently fed body fabric, said folder having means beyond its receiving end for removing the natural curl at the edges of the strip so that the latter enters perfectly flat, and being tubular and mergent from fiat cross section at its receiving end to U-shaped cross section at its delivery end with provision of an uninterrupted passage therethrough whereof the transverse dimension is substantially uniform and slightly greater than the thickness of the strip, whereby the strip edges are maintained flat during traverse of the strip in the folder, said folder also having inwardlydirected opposing lips forming a constricted mouth extending at an angle crosswise of its U-shaped delivery end which constrains the folds 

